Ask a buddy to follow you when you are riding on various terrain (flats, uphill, sprints, etc) and watch your knees from behind. If your knees track pretty straight up and down without wobbling or twisting as you pedal, then you're in really good shape. Some people will need to pay $$$ to fix problems in their pedal stroke that could cause knee injuries down the road. A lot of people are happy with just pointing their cleats straight ahead and aligning their knees with the pedal axles.